Help. Pea sized bump near labia majora

I've had a pea sized bump on my labia majora for the past couple of years. It usually occurs in the same spot. When I touch it, it feels sore but other than that no pain. It also gets swollen and then goes away on its own but every couple of months comes back and has the same routine. I once tried to pop it but it doesn't pop it just feels like a mass of skin. I've gotten STD tested and I'm negative for everything. I just want to see if maybe someone else had this problem and been diagnosed? I'm going to see the doctor soon but just want a little input.  Thank you everyone for helping a girl out!